The clamping piece must be clamped with considerable force with respect to the housing in order to apply a correspondingly large holding force to the end of the guide bar. In this connection, consideration must be given to the fact that substantial torques act on the rearward end of the guide bar because of the forces which act at the forward end of the guide bar and because of the length of the latter.
Experience has shown that even with relatively high bracing forces, the rearward end of the guide bar is displaced relative to the housing in the course of working with the chain saw which is accompanied by a relaxing of the tension in the saw chain. In order to obtain a reliable and safe handling of the chain saw, the work therewith must be interrupted often and the clamping piece loosened which is followed by a retensioning of the saw chain via the tensioning device. Thereafter, the clamping piece must again be screwed tight by applying correspondingly high forces so that the guide bar can be held in the newly adjusted position.
Especially for long guide bars, the forces acting on the guide bar act also on the chain tensioning device whereby the latter becomes greatly affected. The chain tensioning device is provided exclusively for developing the tensioning force and not for taking up high forces occurring during work with the chain saw. Experience in the field has shown that the chain tensioning device is greatly loaded and is often damaged or is rendered completely useless.